Local dependency's dependencies unavailable during postinstall

[chrismwendt]

I'm opening this issue because:

• npm is crashing.
• npm is producing an incorrect install.
• npm is doing something I don't understand.
• Other (see below for feature requests):

What's going wrong?

I'm trying to build a local dependency dep1 during npm install, but dep1's dependencies are not installed under dep1/node_modules, which is causing its build step to fail. npm's flattening behavior seems to be causing the dependencies to be hoisted out of dep1/node_modules directory and into the root ./node_modules. This screenshot captures the situation:

Basically, I expect npm to provide all the dependencies necessary to build the local dependency during postinstall in the same way that the dependencies are available during prepublish when publishing to the npm registry.

How can the CLI team reproduce the problem?

diff --git a/dep1/package.json b/dep1/package.json
new file mode 100644
index 0000000..6494560
--- /dev/null
+++ b/dep1/package.json
@@ -0,0 +1,9 @@
+{
+    "name": "dep1",
+    "scripts": {
+        "postinstall": "ls"
+    },
+    "dependencies": {
+        "left-pad": "1.1.3"
+    }
+}
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..0f39cd1
--- /dev/null
+++ b/package.json
@@ -0,0 +1,5 @@
+{
+    "dependencies": {
+        "dep1": "./dep1"
+    }
+}

• Copy the diff above
• git init && pbpaste | git apply && npm i

supporting information:

• npm -v prints: 5.3.0
• node -v prints: v6.11.3
• npm config get registry prints: http://registry.npmjs.org/
• Windows, OS X/macOS, or Linux?: Mac

[aajtodd]

Also saw this with npm 5.8 / node 9.6.1

Last 4.x series of npm worked ok.

[Aminelahlou]

Hello,
I have exactly the same problem with npm 6.1.0 and node v8.11.2
I have to use npm 5.7 minimum I can't use 4.x series

[Aminelahlou]

I am available this week end if someone wants to pair on this bug 💃